Pulp-screening machine.



P. P. WESTBYE.

PULP SCREENING MACHINE.

Ilm*

col. M A mANoaRAPM ca .wAsmN on. u.

P. P. WESTBYE.

PULP SCREENING MACHINE.

P. P. WESTBYE.

PULP SCREENING MACHINE.

APmcATloN FILED Aue.9.191x.

COLUMBIA PLANoonAPM co..w.sHvNsTm\. u

Patented Sept. 28, 1915.

5 SHEETS-SHEET 3.

P. P. WESTBYE.

PULP SCREENING MACHINE.

APPucATIoN FILED Auai9.1911.

1,155,1 16. Patentedsepn28,1915.

5 SHEETS-SHEET 4.

COLUMBIA PLANouR/PH C0., WASHINGTON, D. c.

P. P. WESTYBYE.

PULP SCREENING MACHINE.

APPucAToN FILED was. 1911.

1,155,1 16. Patentedsept. 28, 1915.

5 sHETssHEET 5.

UNITED STATES PATENT OFFICE.

PEDER P. WESTBYE, F PETERBOROUGH, ONTARIO, CANADA.

PULP-SCREENING MACHINE.

Application led August 9. 1911.

To all whom t may concern:

Be it known that I, Penna P. WEsTYE, a subject of the King of Norway,residing at Peterborough, in the county of Peterborough, Province ofOntario, Canada, have invented certain new and useful Improvements inPulp-Screening Machines, of which the following is a specification.

My invention relates to paper making machinery, and particularly to pulpscreens adapted to separate the finer and usable portions of the pulpfrom the coarse or unusable portions of the material.

The object of the invention is to simplify the structure, as well as themeans and mode of operation of such machines, whereby they will not onlybe cheapened in construction, but will be more efficient in use,economical in operation.r positive in action easily operated andunlikely to get out of repair.

A further object is to provide an improved screening method withimproved. means for supporting the screen and for forcibly dischargingthe pulp against the stationary screen, and furthermore improved meansfor securing an equal distribution of the pulp over a screen surface ofcomparatively large area.

A further object is to provide improved feeding devices for supplyingthe pulp whereby the distributing mechanism will be suppliedsubstantially equally throughout.

With the above primary and other incidental objects in view as will morefully appear in the specification, the invention consists of thefeatures of construction, the parts and combinations thereof and themode of operation, or their equivalents, as hereinafter described andset forth in the claims.

Referring to the drawings, Figure 1 is a vertical longitudinal sectionalview of the assembled machine. Fig. 2 is an end elevation of theassembled machine showing the pulp supply conduits. Fig. 3 is atransverse vertical sectional view on line ma: of Fig. 1. showing theintake end of the rotary distributer, and the discharge orifices of thesupply conduits. Fig. 4 is a plan view of the pressure equalizingchamber for the pulp supply. Fig. 5 is an end elevation of the revolublerotor or distributor, viewed from the discharge end. Fig. 6 is a detailtransverse sectional view of one of the rotor or distributer vanes. Fig.7 embodies five different longitudinal sectional views of theSpecification of Letters Patent.

Patented Sept. 28, 1915.

Serial No. 643,232.

rotor or distributer vanes, on lines I-I, H411, IIIA-III, IV-IV and V-Vrespectively, of Fig. 1 showing the variations in the curvature of thevanes or blades. Fig. 8 is an elevation of one of the semi-annularscreen supporting frames. Fig. 9 is a vertical sectional view throughthe lower half screen and its supporting frame showing the engagement ofthe screen support with the frame of the machine. Fig. 10 is a detailsectional view of the screen attachment means.

Like parts are indicated by similar characters of reference throughoutthe several views.

In constructing the machine there is employed a seinrannular or troughshaped body l, having at one end thereof an annular head 2 and at theopposite end an annular housing 3, which forms an outlet chamber for thescreened pulp as here after described. The semi-annular body l forms thelower half of a horizontal cylindrical casing, the upper half of whichcomprises a removable semi-annular cover 4 supported upon the annularhead 2 and housing 3 and on the upper edges of the semi-annular body 1,and preferably secured in place by means of longiturinally disposedangle irons 5 5.

Extending centrally through the casing is a revoluble shaft 6 journaledin bearings 74-7 mounted in suitable brackets 8,8 proiecting from theannular head 2 and the housing 3.

At its inner side the annular housing 3 is provided with an interiorperipheral iange 9 upon which is supported the vertical stationary pulpscreen which forms a perforated diaphragm between the annular head 3 andthe main casing. The screen plates are preferably two in number, eachsemi-annular in shape and secured upon semiannular supporting frames orspiders 11, shown in detail in Figs. 8 and 9. It is obvious that thescreen plates and supporting frame therefor might be single continuousannular members or the screen plate and supporting frame might bedivided into a plurality of segmental sections of any proportion.

Referring particularly to Figs. 8 and 9, the supporting frame for thescreen comprises a central half hub portion 12, and a semi-annular rimportion 13 the faces of which lie in a common plane and to which thescreen plate is directly attached by bolts lli) or rivets through theholes 14 in the hub and rim portions. The hub portion 12 and rim portion13 are connected by radial arms 15 which are further united by aconcentric tie 16 which is further connected to the rim 13 by additionalradial arms 17. It is to be understood that the particular arrangementof arms and ties is not essential, but that such arms and ties may beincreased or diminished. or rearranged to meet different conditions ofservice.

As will be seen in Fig. 9 the radial arms 15 and tie 1G do not extendflush with the faces of the hub and rim portions, and the screen platel0 does not rest directly upon the radial arms and tie, but that thearms and tie are located somewhat below the plane of the faces of thehub and rim portions, whereby a clearance space 18 is providedintermediate the screen plate and arms.

Located at intervals on the arms 15 and tie 16 are bosses 19 whichproject into proximity to the screen plate 10. Each of the bosses 19 areperforated for the reception of retaining bolts Q0 by which the screenplate 10 is secured in place. The retaining bolts Q0 are supplemental tothe bolts of rivets by which the margins of the screen plate is securedto the hub and rim portions.

In order to reduce to minimum the resistance afforded by the heads ofthe retaining bolts 2O to the passage of the pulp, the heads of saidbolts are formed conical whereby any pulp striking the bolt heads willbe deflected laterally onto the screen plate.

ln order to reduce the liability to breakage of the screen plate due tothe great pressure and strain to which the screen plate is subjected,the central portions of the screen plate are yieldingly or resilientlysupported upon the bosses 19 by means of rubber or other resilientcollars 21 located upon the retaining bolts 2O on opposite sides of thescreen plate 10. It is obvious that helical springs might be substitutedfor the resilient collars 21. The screen plate frames are removablysecured upon the interior flange i) of the annular head The uppersemiannular screen plate frame is attached to the flange 9 by means ofangle irons or brackets Q2 bolted to the rim 13 of the screen plateframe and to the flange 9. The lower half frame is provided about itsperiphery with a plurality of radially disposed studs 23 which engagewithin the groove Q4 of a grooved flange 25 projecting inward from thelower half of the interior flange 9. The lower half frame may be removedafter the removal of the upper half frame by a partial rotation of thelower half frame within the flange 25 and about the shaft G whereby theradial studs will be caused to pass out of the groove 24.

Carried upon the shaft 6 is a revoluble rotor or runner which operatesby centrifugal tendency to distribute the pulp equally over the extendedsurface of the screen plate. The rotor comprises a conical or bellshaped shell 2G, the larger end of which is directed toward the verticalscreen plate 10, having therein a plurality of radial vanes or blades27. The shell 2G is continuous or imperforate throughout. except forcertain air1 vents hereafter mentioned. lVhile the vanes or blades Q7are radially disposed when viewed from the end. these vanes are somewhathelical or winding in their longitudinal relation. The shell QG, thevanes 2T, and the hub or sleeve Q8 are preferably formed integral. butit is obvious that such parts might be formed separate and subsequentlyassembled. At the intake and discharge ends of the vanes the vanes arecurved rather abruptly in opposite directions. as shown in Fig. 7 thedegree of curvature varying in proportion to the distance from the axisor shaft, as does also the inclination or pitch of the vanes. Theinclination or pitch of the vanes as well as the curvature of the vanesat the intake and discharge ends is mathematically calculated inaccordance with the lineal velocity of the pulp in comparison with thecircumferential velocity of the rotor at the given point. The necessarycurvature may be ascertained with accuracy by well known engineeringformulas and diagrams` the curvature varying in accordance with thespeed at which it is desired to revolve the rotor and the head orpressure of the pulp supply. The sections of vanes shown in Fig. 7 aredesigned for a rotor speed of two hundred and seventy five to threehundred revolutions per minute, with a pulp discharge velocity of twentyfeet per second.

The pulp supply enters the smaller end of the rotor and after travelingalong the vanes 2T is discharged from the large end thereof against thescreen plate 1f). It is to be noted that the screen plate 10 ispeipendicular to the axis of rotation of the rotor or distributer. Tomaintain the pulp at substantially even depth throughout the width ofthe vanes, and to prevent an excess of pulp passing to the outer edge ofthe vanes under the influence of centrifugal tendency, there areprovided on the advance or pulp engaging faces of the vanes Q7, aplurality of ribs Q9 projecting from the vanes and providing severalgradually widening channels through which the pulp flows. Inasmuch asthe rapid rotation of the rotor might cause a suction or partial vacuumat the rear or under side of each of the vanes, which might disturb theeven distribution of the pulp over the next succeeding vane, there areprovided in the exterior shell 2G of the rotor at points to the rear ofeach of the vanes QT, air vents 30 by which the air pressure within andoutside the shell may be maintained in equilibrium. It will also be seenthat at Cri its discharge end the conical shell Q6 is slightly curvedforward, which serves to overcome the outward movement of the pulp dueto centrifugal tendency as it leaves the rotor, and to confine the pulpdischarge to the area of the screen plate. At is intake end the rotor isprovided with a flange 31 which overhangs the discharge nozzles of thepulp supply conduit thereby preventing waste or leakage.

lulp is supplied to the machine through the conduit 32. The supply ofpulp through the conduit 32 is frequently irregular, and the length ofthe conduit 32 varies under different condition and in different mills,thereby supplying the pulp under different head or various pressures. Inorder that the pulp may be supplied to the rotor or distributor at aconstant pressure whereby the discharge velocity of the pulp may bemaintained at the given ratio for which the machine is designed,pressure equalizing means is provided. This equalizing means comprises achamber 33 into which the conduit 32 discharges, from which lead aplurality of supply conduits 34 and 35. These conduits 34 and 35 projectwithin the chamber 33 above the bottom thereof whereby the pulpdischarged by the supply conduit 32 collects in the bottom of thechamber 33 and overflows the upper ends of the supply conduits 34 and'Thus the current of pulp carried by the conduit 32 is interrupted, andthe rotor is supplied with pulp under a constant head equal to theheight of the upper ends of the conduits 34 and 35 above the dischargenozzles to be described. It is obvious that the chamber 33 may belocated at any desired height above the rotor, thereby supplying thepulp to the rotor under different heads or pressures. The supply conduit32 is off set in its relation with the conduits 34 and 35 as shown inFig. 4, whereby the pulp cannot directly enter the conduits 34 and 35under pressure as it is discharged from the conduit 32, but must enterthe chamber 33 from which it overflows the conduits 34 and therebymaintaining the constant head or pressure.

Projecting inward from the annular head '2 and extending within theannular flange 3l of the rotor are a plurality of radially disposeddischarge nozzles with which the conduits 34 and 35 communicate. Theobjiect of the plurality of nozzles is to supply the pulp equallytliroughout the entire intake of the rotor. In the drawings three of thenozzles 36 have been shown. It is obvious however that any desirednumber of nozzles 2G and corresponding supply conduits 34 and 35 may beemployed. In as much as the conduits supplying the nozzles directingpulp to the lower portion of the rotor are longer than the conduit 34supi plying the upper portion of the rotor, the

head of pulp or pressure will be greater in the conduits than in theconduit 34, therefore the conduits are made of slightly less diameterthan the shorter conduit 34, thereby equalizing the pulp discharge, thenozzles 36 of the conduits 35 having correspondingly smaller orifices asclearly shown in Fig. 3. Further the imaginary circular path upon thescreen plate supplied with pulp from any given point of the rotor or anygiven channel formed between the ribs 29 of the vanes Q7, beingproportionately greater as such point or channel is removed from theaXis of the rotor, a gradually increasing supply of pulp is required ina radial direction. In view of this the nozzles 3G are somewhat sectorshaped, the sides of the nozzles being divergent, and more widelyseparated at the outer than at the inner portions. This variation inwidth of the nozzle insures the outer portions of the screenv plate ofgreater circumferential length being fully supplied with pulp equallywith the central portions of the screen plate of less circumferentiallength. Thus the shape of the nozzles further insures the evendistribution of pulp over the whole surface of the screen plate.

The rapid rotation of the rotor is inclined to create a suction at theintake end. which not only facilitates the feeding of the pulp throughthe conduits 34 and and the nozzles 36, but it also tends to draw intothe rotor a current of air which might interfere with or disturb thedistribution of the pulp upon the rotor vanes. To obviate this there isprovided upon the inner side of the annular head 2 a flange 37projecting within the terminal flange 3l of the rotor. This flangeprevents the entrance of an excessive amount of air and also the loss ofpulp through leakage.

As before stated the top 4 of the main casing is removable whereby therotor or screen plate may be inspected or repaired. There are alsoprovided manholes 38 in the annular walls of the housing 3 and likewisecovered manholes, (not shown) in the head of said housing.

The pulp is supplied to the equalizing chamber 33 through the conduit32, from which chamber it is conducted to the rotor by the conduits 3land 35, being discharged into the rapidly revolving rotor through thenozzles 36. The centrifugal tendency due to the rapid rotation of therotor tends to spread the pulp over the vanes or blades of the rotorfrom which the pulp is forcibly discharged against the stationaryvertical screen plate l0. The finer or usable portions of the pulp passthrough the perforations of the screen plate into the outlet chamberformed by the annular housing 3, from which thescreened pulp isconductedthrough the outlet conduit 39. The. enarser portions of the pulp orunusable portions comprising splinters, chunks or lumps of pulp, andforeign matter known as tailings failing to pass through'the screenplate fall to the bottom of the semi-annular body 1 and escape throughthe outlet 40 in the bottom of said member. In working certain classesof material it may be found desirable to provide a water spray directedupon the screen plate 10 to keep the perforations of the plate clear andprevent the clinging of tailings thereto. Such spray devices being wellknown are not shown in the drawings.

ll'hile the parts above described are preferably employed as shown inthe drawings, that is with the rotor revolving on a horizontal axis andthe screen plate in a vertical position. it is obvious that themechanism might be employed in a vertical position. with the screenplate horizontal.

From the above description it will be apparent that there is thusproduced a machine of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, propoxtions,detail construction, and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages.

Having thus described my invention I claim:

1. In a pulp screening machine, a casing, a screen member in saidcasing, a supporting frame for the screen member. a plurality of bosseson the supporting` frame upon which the screen member rests, whereby thescreen member will be spaced away from the supporting frame, adistributer adapted to distribute the pulp over the screen surface, anda pulp supply leading to the distributer.

2. In a pulp screening machine, a casing, a screen member within thecasing, a supporting frame for the screen member, resilient abutmentsfor the screen member adapted to yieldingl'v support the screen againstthe impact of the pulp discharged thereon, a distributer for the pulpand a pulp supply conduit leading to the distributer.

3. In a pulp screening machine, a casing, a screen member within thecasing, a supporting frame for the screen member, a plurality ofattachment bolts securing the screen member to the supporting frame.resilient collars about said bolts on opposite sides of the screen, adistributer for the pulp, and a pulp supply conduit leading to thedistributer.

4. In a pulp screening machine, a casing, a screen member within thecasing, a supporting frame for the screen member, a plurality of boltsattaching the screen to the supporting frame, conical heads upon theattachment bolts whereby portions of pulp discharged against the boltheads will be deflected onto the screen, a' distributer for the pulp,and a pulp supply conduit leading to the distributer.

5. In a pulp screening machine, a casing, a screen member within thecasing, a supporting frame for the screen member, a grooved flangewithin the casing, projections carried by the screen supporting frameextending within the groove of the flange whereby the screen and framewill be detachably engaged therewith.

6. In a pulp screening machine, a casing, a vertically disposed screenmember within the casing, resilient supporting means for the screenmember, a distributer for the pulp and a pulp supply conduit.

7. In a pulp screening machine, a casing, a screen member, a rotarydistributer comprising an annular shell, a plurality of vanes spirallyarranged within the shell adapted to discharge the pulp in a directionsubstantially parallel with the axis of rotation, a plurality of ribslocated on the advance side of the vanes and extending from the intaketo the discharge ends thereof, a pulp supply leading to the distributer,and means to rotate the distributer.

8. In a pulp screening machine, a easing, a screen member, a rotarydistributer comprising an annular shell and a plurality of vanes withinthe shell, the shell having therein a plurality of air vents adjacent tothe rear sides of the vanes, a pulp supply conduit leading to thedistributer, and means for rotating the distributer.

9. In a pulp screening machine, a casing, a screen member, a rotarydistributer, a pulp supply conduit leading to the distributer, adischarge nozzle for the supply conduit seetor shaped in cross sectionand radially disposed in relation to the axis of the distributer.

10. In a pulp screening machine, a casing, a screen member, a rotarydistributer, a pulp supply conduit discharging into the distributer at apoint eccentric therewith, a nozzle for the supply conduit having itsgreatest dimension in a direction radial to the axis of the distributer.

11. In a pulp screening machine, a casing, a screen member, a rotarydistributer, a pulp supply conduit leading to the distributer, a

nozzle for said conduit having a substantially V shaped dischargeorifice eccentrically located in relation with the axis of rotation.

1Q. In a pulp screening machine, a casing a substantially verticallydisposed screen member, a rotary distributer, a pulp supply conduit, aplurality of nozzles with which the supply conduit communicates, saidnozzles being eccentrically arranged in radial relation about the axisof the distributer and discharging thereinto.

13. In a pulp screening machine, a casing, a screen member, adistributer, a pulp supply conduit, a plurality of radially disposedslotted nozzles discharging into the distributer at different heights,said nozzles being of different cross area according to the relativeheight of the several nozzles whereby the varying height of the headwill produce an equal discharge through the several nozzles.

14. In a pulp screening machine, a casing, a substantially verticallydisposed screen member, a distributer rotating upon a horizontal axis,and a bifurcated pulp supply conduit, the branches or' which dischargeinto the distributer at diiierent heights and are of diierent relativecross area in accordance with their relative height of discharge.

15. In a pulp screening machine, a casing, a substantially verticallydisposed screen member, a distributer rotating upon a horizontal axis,and a plurality of pulp supply conduits of different cross areadischarging into the distributer at points eccentric to the axis ofrotation.

16. In a pulp screening machine, a casing, a screen member, adistributer, a pulp supply conduit, a reservior into Which the pulpsupply conduit having outlet-s of diierent areas discharges, a pluralityof auxiliary conduits leading from the reservoir to the distributer,said reservoir being adapted to interrupt the head of pulp Within theconduit whereby the pulp will be supplied to the distributer underaconstant head equivalent to the height of the reservoir above thedischarge oriiices of the auxiliary conduits.

17. In a pulp screening machine, a easing, a screen member, adistributer, a pulp supply conduit, a reservoir into which the pulpsupply conduit discharges, a plurality of auxiliary conduits leadingfrom the reservoir to the distributer, the intake orifices of saidauxiliary conduits being located above the bottom of the reservoir,substantially as speciiied.

1S. In a pulp screening machine, a screen member, a rotary distributer,a pulp supply conduit leading thereto, having a divergent dischargeoriiice, radially disposed in relation with the distributer said oricebeing of greater width at its outer end than at the end adjacent to theaxis of the rotor.

19. In a pulp screening machine, a screen member, a rotary distributer,a pulp supply conduit leading to the distributer, and a plurality ofslotted discharge orifices radially disposed in relation with thedistributer through which the pulp is supplied thereto.

In testimony whereof, I have hereunto set niy hand this 31st day ofJuly, 1911.

PEDER I. WESTBYE.

Witnesses:

Lo'r'rrn DAVIS, J. E. L. GOODWILL.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

